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TREATMENT OF VOLATILE ORGANIC COMPOUNDS IN WASTE GASES USING A TRICKLING BIOFILTER SYSTEM: A MODELING APPROACH
Citation:
Smith, P. J., P. Biswas, M. T. Suidan, AND R C. Brenner*. TREATMENT OF VOLATILE ORGANIC COMPOUNDS IN WASTE GASES USING A TRICKLING BIOFILTER SYSTEM: A MODELING APPROACH. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/A-94/054 (NTIS 94-159316), 1994.
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Description:
Biofiltration represents a novel strategy for controlling VOC emissions from a variety of industrial processes. As commercial applications of these systems increase, sophisticated theoretical models will be useful in establishing design criteria for providing insights into important process mechanisms. Modeling approach for a trickle bed biofilter was developed in this work that incorporates several accepted idealizations about biofilm systems. With the use of such idealizations, there is a need for estimating parameters by conducting controlled experimental studies. The biofilter model proposed quantifies the treatment of a single component VOC waste strewn in a system operating at steady state. Effects of biological growth on the hydrodynamics of the flow are accounted for and the full Monod kinetic rate expression is used in describing VOC consumption in the biofilms. Relationship between the flux into a biofilm and the corresponding thickness is also incorporated into the model. This leads to a prediction of a biofilm profile through the bed depth with thicker films at the inlet of the filter where concentrations are higher. Performance was shown to be poor at steady-state conditions where the inlet VOC concentrations were low. This is due to a limiting gas phase concentration below which the biofilms can not be sustained. Eight dimensionless groups were identified that completely determine a unique solution of the model equations. or a given VOC and biofilter packing media, efficiency can be expressed as a function of a one of these groups. The resulting efficiency curves can be reduced to a algebraic equation that can be used as a form for a simple empirical design correlation.